android socket closed,Android Socket Exception “socket is closed”
问题
When I try to run a test composed of an echo server and an android client with the following code, I always get the exception msg "socket is closed". This code can simply send msg to server, and receive msg from server, but if you want to do both at the same time, it just doesn't work... I am very curious why it will lead to this kind of problem, and how should I fix it if I want it to be able to first send msg to echo server
and then receive msg from echo server?
// Server IP address
InetAddress serverIp;
// try to connect Server
try {
// set up server IP address
serverIp = InetAddress.getByName("192.168.17.1");
// set up port
int serverPort=12345;
// initiate socket connection
Socket clientSocket=new Socket(serverIp,serverPort);
BufferedOutputStream out = new BufferedOutputStream(clientSocket.getOutputStream());
out.write("Send From Android1111, stitch ".getBytes());
out.flush();
//wait to receive Server's msg
BufferedReader br =new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
total.toString();*/
// Display received msg with Toast
Toast.makeText(getApplicationContext(), br.readLine(), Toast.LENGTH_SHORT ).show();
//close connection
clientSocket.close();
// out.close();
// out = null;
} catch (IOException e) {
// display exception with Toast
Toast.makeText(getApplicationContext(),e.toString(), Toast.LENGTH_SHORT).show();
}
unfortunately, it still doesn't work ...I followed your instruction and modify the code to:
// set up Server IP address
serverIp = InetAddress.getByName("192.168.2.2");
// set up Server port
int serverPort=12345;
// initiate socket connection
Socket clientSocket=new Socket(serverIp,serverPort);
// open input and output stream
OutputStream out = clientSocket.getOutputStream();
InputStream in = clientSocket.getInputStream();
//send msg
out.write("Send From Android1111, bitch ".getBytes());
// receive msg from server
byte[] buffer = new byte[in.available()];
in.read(buffer);
String rMsg = new String(buffer);
Toast.makeText(getApplicationContext(), rMsg, Toast.LENGTH_LONG ).show();
//close input and output stream
in.close();
out.close();
//關閉連線
clientSocket.close();
} catch (IOException e) {
// 出錯後顯示錯誤訊息Toast
Toast.makeText(getApplicationContext(),e.toString(), Toast.LENGTH_SHORT).show();
}
for helper's convenience, here's the python written code for server part:
# Practice Echo Server Program written in Python
import socket
# host = '' means it binds to any available interface
host = ''
port = 12345
# socket() function returns a socket object whose methods implement the various socket system calls.
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
# Bind the socket to address.
s.bind((host,port))
# Listen for connections made to the socket. The backlog argument specifies
# the maximum number of queued connections and should be at least 0;
# the maximum value is system-dependent (usually 5), the minimum value is forced to 0.
s.listen(5)
# Accept a connection. The socket must be bound to an address and listening for
# connections. The return value is a pair (conn, address) where conn is a new socket
# object usable to send and receive data on the connection, and address is the address
# bound to the socket on the other end of the connection.
conn, addr = s.accept()
print 'Connected by', addr
# Receive data from the socket. The return value is a string representing the data received.
# The maximum amount of data to be received at once is specified by bufsize. See the Unix
# manual page recv(2) for the meaning of the optional argument flags; it defaults to zero.
# Note For best match with hardware and network realities, the value of bufsize should be
# a relatively small power of 2, for example, 4096.
while 1:
data = conn.recv(1024)
if not data: break
print 'received data is : ', repr(data)
conn.send(data)
conn.close()
回答1:
I assume you are doing the right things in the wrong order. May be the server is too fast and when you are trying to read the response it is already received and gone.
Following the rules presented in the tutorial Reading from and Writing to a Socket
Open a socket
Open an input stream and output stream to the socket.
Read from and write to the stream according to the server's protocol.
Close the streams.
Close the socket.
Do you see the difference? First open Input and Output stream and then start sending your request.
I am sure that if you stick to this order it will work.
回答2:
I had a similar issue, solved it by editing the gradle.properties file to allow for proxy connections. I added the foregoing lines as explained on https://github.com/facebook/react-native/issues/2726 by Nadeem Shaik
systemProp.http.proxyHost=proxyHost
systemProp.http.proxyPort=proxyPort
systemProp.https.proxyHost=proxyHost
systemProp.https.proxyPort=proxyPort
回答3:
Your application needs INTERNET permission in your AndroidManifest.xml
来源：https://stackoverflow.com/questions/8839019/android-socket-exception-socket-is-closed